Certain 2-substituted cephalosporins

ABSTRACT

Disclosed herein are novel analogs of cephalosporins. They differ from prior art compounds in that they are substituted in the 2-position and can be prepared by reacting known cephalosporins with an active source of halogen to form a 2halogenated intermediate. Substitution of the thus formed intermediate can be accomplished with various substituents. The compounds of this invention are useful antimicrobial and antibacterial agents.

United States Patent 1 [111 3,852,282 Dolfini Dec. 3, 1974 CERTAIN Z-SUBSTITUTED 3,660,395 5/1972 Wright et al. 260/243 c CEPHALOSPORINS Inventor: Joseph E. Dolfini, PrincetomNJ.

Assignee: E. R. Squibb & Sons, Inc., Princeton, NJ.

Filed: Oct. 16, 1972 Appl. No.: 298,172

Related US. Application Data Continuation-impart of Ser. No. 812,386, April 1, 1969, abandoned.

US. Cl. 260/243 C, 424/246 Int Cl C07d 99/24 Field of Search 260/243 C References Cited UNITED STATES PATENTS 4/1970 Morin et al. 260/243 C 5/1971 Cooper 260/243 C OTHER PUBLICATIONS Burger; Medicinal Chemistry; 2nd Edition; p. 42, 497.

Primary Examiner-+Richard J. Gallagher Assistant Examiner-Mary C. Vaughn Attorney, Agent, or FirmLawrence S. Levinson; Merle J. Smith; Stephen B. Davis [5 7] ABSTRACT Disclosed herein are novel analogs of cephalosporins. They differ from prior art compounds in that they are substituted in the 2-position and can be prepared by reacting known cephalosporins with an active source of halogen to form a 2-halogenated intermediate. Substitution of the thus formed intermediate can be accomplished with various substituents. The compounds of this invention are useful antimicrobial and antibacterial agents.

5 Claims, No Drawings 1 CERTAIN Z-SUBSTT'TUTEB C EPHALOSPORINS This application is a continuation-in-part of Ser. No. 812,386 filed Apr. 1, 1969 now abandoned.

This invention relates to A -cephems having the formula:

wherein:

R is iodo, chloro, bromo, lower alkoxy, lower alkenyloxy, lower alkynyloxy, aryloxy, lower alkanoyloxy, lower alkylthio, lower alkylenylthio, lower alkynylthio, arylthio, aroylthia or lower alaryl-E, thienyl (especially thien-Z-yl aryl lowear alkyl-L,

The cephems which may be utilized in the practice of this invention have the formula:

..r, i w UV 9 lower alkyl-H,

I thienylacetyl and a ryloxy lower alkyl kanoylthia; R and R A and M are as hereinafter described. Those compounds of this invention, wherein iodo, chloro and bromo are in the 2- position, are considered to be intermediates in the preparation of the end products.

I For purposes of this invention the following definitions are applicable: lower alkyl, lower alkenyl and' The terms aroyloxy, lower alkanoyloxy, thia-aroyl and thia-lower alkanoyl are intended to mean ll Y lower .ilbik il'.

respectively.

The compounds of the invention are prepared by reacting a A -cephem compound with an active source of halogen to yield the corresponding cephalosporin substituted in the 2-position with a chloro, bromo, or iodo.

This intermediate is highly reactive and may be readily modified by displacement of the halogen by a nucleophilic species of formula:

wherein R is lower alkyl, lower alkenyl, lower alkynyl, aryl or acyl, and Y is oxygen or sulfur.

An active source of halogen may be utilized in the practice of this invention. Examples of those which may be utilized are N-bromosuccinirnide, N- chlorosuccinimide, sulfuryl chloride, tbutylhypochlorite, molecular iodine, molecular bromine, and so forth.

and when R and R are acyl, the RR N group is a succinimido and phthalimido.

Compounds wherein R R are hydrogen may be prepared by either of two routes:

1. cleavage of a phthalimide compound wherein RR N is phthalimido by hydrazine or,

2. cleavage of a 7-aroylamino compound where R is hydrogen and R is benzoyl by themethod shown in Australian Pat. No. 19,902/62.

These amines are converted to the amides of this invention by the standard acylation reactions described in R. R. Chauvette, E. H. Flynn, B. G. Jackson, E. R. Lavagnino, R. B. Morin, R. A. Mueller, RQP. Pioch, R. W. Roeske, C. W. Ryan, J. L. Spencer, and E. Van Heyningen, J. Amer. Chem. 500., B4, 3401 (1962); E. Van Heyningen, J. Med. Chem., 8, 22 (1965); E. Van Heyningen and C. N. Brown, ibid., 8, 174 (1965); J. L. Spencer, F. Y. Siu, E. H. Flynn, B.G. Jackson, M. V. Sigal, H. M. Higgins, R. R. Chauvette, S. L. Andrews, and D. E. Bloch, Antimicrob. Ag. Chembthen, 1967, 573; J. L. Spencer, F. Y. Siu, B. G. Jackson, H. M. Higgins, and E. H. Flynn, J. Org. Chem., 32, 500 (1967); L. B. Crast, Jr., and J. M. Essery, U.S. Pat. No. 3,352,858 (19.67); J. L. Spencer, E. H. Flynn, R. W. Roeske, F. Y. Siu, and R. R. Chauwette, J. Med. Chem., 9, 746 (1966); M. Kurita, S. Atarashi, K. Hattori, and T. Takano, J. Antibiot., Ser. A, 19, 243 (1966), R. B.

' Morin, B. G. Jackson, R. A. Mueller, E. R. Lavagnino,

W. B. Scanlon, and S. L. Andrews, J. Amer. Chem. Soc., 85, 1896 (1963); E. Van Heyningen, Advances in Drug Research, Academic Press, New York (1967.). Vol. 4, Cephalosporins, pp. 1-70. The salts of the new compounds are metal salts, above all, the salts of therapeutically useful metals of the groups of alkali metals or alkaline earth metals such as sodium, potassium, ammonium or calcium or salts with organic bases, for example, with triethylamine, N- ethylpiperidine, dibenzylethylenediamine, N,N'-bis- (dehydroabiethyl)ethylenediamine or procaine or others such as are known to be useful for preparing salts of penicillins or cephalosporins.

The new compounds are very stable towards penicillinases. Under the conditions of therapeutic application they are stable. They display antibacterial activity towards Gram-positive bacteria, for example, Staphylococcus aureus, and especially towards penicillinresistant strains but above all, towards Gram-negative bacteria, for example, Escherichia coli, Klebsiella pneumoniae, Salmonella typhosa and Bact. proteus. They may therefore be used for combating infections caused by gram-positive or gram-negative micro organisms, and also as additives for animal feedstuffs and in the preservation of foodstuffs or as disinfectants. For these purposes they are administered in the same way as other semi-synthetic cephalosporins for instance 7- (thienylacetylamino)-cephalosporanic acids.

Hitherto, there has been no attempt to halogenate the cephalosporin starting materials of this invention in view of the unsaturation in the 3-position. Therefore, it was not expected that this reaction would yield the 2-halo semi-synthetic cephalosporanic acid of this invention in a relatively good yield.

The reaction between the cephalosporin derivative and the halogenating agent is carried out under ambient conditions and may require a free radical source or initiator such as azo-bis (isobutyronitrile), benzoyl per- 2-methoxynaphthol, a-methoxy-3, 4-dichlorophenyl acetic acid, pyridyI-B-acetic acid, butylthioacetic acid, acetic acid, and so forth.

The following examples illustrate the invention, all temperatures being in degrees Centigrade:

EXAMPLE 1 7-Phthalimido-3-acetoxy carboxylic acid A solution of 2.13 g. of 7-aminocephalosporanic acid and 2.3 g. of sodium bicarbonate in 80 ml. of acetonewater (1:1) is cooled to C.; a solution of 2.04 g. of phthaloyl chloride in ml. of acetone is slowly added over about a ten-minute interval. After vigorous agitation for 1.5 hours at 5 C., the reaction mixture is diluted with 50 ml. water and the pH adjusted to 8 with a small amount of aqueous sodium bicarbonate solumethyl-A -cephem-4- tion. The solution is extracted with ethyl acetate and then acidified with ice-cold aqueous lO'percent hydrochloric acid to pH 2. Extraction with 50 ml. of ethyl acetate isolates the product; after drying over sodium sulfate, the solution is filtered and evaporated at reduced pressure at ambient temperature. The residue of crude product, 1.2 g., solidifies on standing. Trituration with cold ether leaves apurified material, 0.8 g. The infrared spectrum showed in chloroform absorption maxima at 5.60 11.. and 5.75-5.80 pt.

EXAMPLE 2 Methyl ester of 7-phthalimido-3-acetoxy methyl-A -cephem-4-carboxylic acid A solution of the product obtained from Example 1 in dioxane is treated with an excess of ethereal diazomethane. After allowing the reaction to proceed to completion, acetic acid is added to destroy any excess diazomethane. Ether is then added to dilute the solution, which is followed by washing with successive treatments of dilute aqueous sodium bicarbonate and cold 2 percent aqueous hydrochloric acid. The ethereal solution is dried with sodium sulfate and evaporated. The residue is triturated with ether. The thus formed ester, when recrystallized from acetone hexane, is a pure white solid with a m.p. of 159C.

EXAMPLE 3 EXAMPLE 4 7-Phthalimido-3-hydroxymethyl-Z-bromo-A -cephem- 4-carboxylic acid, 'y-lactone A suspension of 68 mg. of 7-phthalimido-3- hydroxymethyl-A -cephem-4-carboxylic acid 'y-lactone, 36 mg. of N-bromosuccinimide and about one mg. of azo-bis(isobutyronitrile) in 25 ml. pure chloroform (purified by distillation from phosphorous pentoxide) is placed under a nitrogen atmosphere and stirred at room temperature for one hour. This layer chromatography (ethanol/benzene on silica gel) indicated the absence of starting materials. The solution is washed with ice-cold 5 percent aqueous sodium bicarbonate, then dried with sodium sulfate, filtered and evaporated at reduced pressure at ambient temperature. The product is obtained as a powdery solid in nearly quantitative yield. Purification is effected by crystallization of a sample from acetone-ether, a white solid, m.p. 222-224 C., being obtained.

EXAMPLE 5 7-Phthalimido-3-hydroxymethyl-2-methoxy-A cephem-4-carboxylic acid, 'y-lactone A suspension of mg. of 7-phthalimido-3- hydroxymethyl-2-bromo-A -cephem-4-carboxylic acid, y-la'ctone in 30 ml. of methanol is stirred at ambient temperature. The reaction mixture is maintained at a neutral pH by the addition of triethylamine. After the reaction is completed, the solution is evaporated at reduced pressure. The residue is taken up in chloroform and washed with water, dilute aqueous hydrochloric acid and dilute aqueous sodium bicarbonate, then dried over sodium sulfate and evaporated at reduced pressure. The residue crude product is purified by chromatography on 20 g. of Florisi]. The column is developed with benzene-chloroform (1:1) and the pure product subsequently removed by elution with methanolchloroform (1:9). The product crystallized from methanol yields a cream-colored solid, m.p. l87-l90 C.

EXAMPLE 6 Methyl-3-( acetoxy-methyl -2-bromo-7-phthalimido- A cephem-4-carboxylic acid, methyl ester 416 Mg. of methyl ester of 3-(acetoxymethyl)-7- phthalimido-A -cephem-4-carboxylic acid in 50 ml. of pure chloroform (purified by distillation from phosphorous pentoxide) is treated with 178 mg. of N- b'romosuccinimide and about three mg. azobis(isobutyronitrile) under a nitrogen atomosphere at room temperature until thin layer chromatography showed the absence of starting material. The reaction mixture is chilled both to below 5 C. and washed with ice-cold aqueous 5 percent sodium bicarbonate and then dried with sodium sulfate, filtered, and evaporated at reduced pressure at about ambient temperature to recover the desired product for further reactions.

EXAMPLE 7 2-Methoxy-3-(acetoxymethyl)-7-phthalimido-A cephem-4-carboxylic acid, methyl ester A suspension of 200 mg. of 3-(acetoxymethyl)- Z-bromo-7-phthalimido-A -cephem-4-carboxylic acid, methyl ester in 40 ml. of methanol is stirred at room temperature for two hours with the addition of triethylamine being used to maintain a neutral solution. After the reaction is completed, the solution is evaporated at reduced pressure; the residue is taken up inethyl acetate and the solution washed with cold aqueous 5 per cent sodium bicarbonate, cold aqueous 5 percent hydrochloric acid, saturated aqueous sodium chloride. After drying over sodium sulfate, the solution is evaporated at reduced pressure at ambient temperature. The product is deposited as a powdery solid.

EXAMPLE 8 2-Bromo-7-phenylacetylaminocephalosporanic acid One millimole of the 7-phenylacetylaminocephalosporanic acid and one millimole of N-bromosuccinimide in 50 ml. of chloroform (purified by distillation from phosphorous pentoxide) are stirred with 34 mg. of

azo-bis(isobutyronitrile) at room temperature under nitrogen. The crude product is obtained by evaporating the chloroform solution and triturating the residue with hexane, an amorphous powder results EXAMPLE 9 Reacting equimolar quantities of 2-bromo-7- phenylacetylamino-cephalosporanic acid and ethanol in the presence of triethylamine at a neutral pH in THF,

the product IS 2-ethoxy-7-phenylacetylamino-cephalosporanic acid.

EXAMPLE 10 Following the procedure of Example 8 but utilizing 7-benzamidocephalosporanic acid in lieu of 7- phenylacetylamino-cephalosporanic acid, the product recovered is 2-bromo-7-benzamido-cephalosporanic acid.

EXAMPLE l'l EXAMPLE l2 Utilizing triethylamine salt of acetic acid in dimethylformamide in lieu of ethanol in the procedure of Example 9, the product formed is 2-(acetoxy) 7- phenylacetylaminocephalosporanic acid.

EXAMPLE l3 Phenol is reacted with 2-bromo-3-methyl-7- phenylacetamido-cephalosporanic acid, methyl ester under conditions similar to those set forth in Example 9, the product formed is 2-phenoxy-3-methyl 7- phenylacetamido-cephalosporanic acid, methyl ester.

EXAMPLE 14 Following the procedures of Example 9 but utilizing S-phenylthioacetic acid in lieu of ethanol the product recovered is 2[S-phenylthioacetyl]-7- phenylacetylamino-cephalosporanic acid, methyl ester.

EXAMPLE 15 Utilizing thiophenol in lieu of ethanol in Example 9, the product recovered is 2-thiophenyl-7 thienylacetylamino-cephalosporanic acid.

EXAMPLE .16

2-Chloro-7-thienylacetylamino-cephalosporanic acid One millimole of 7-thienylacetylamino-cephalosporanic acid and l millimole of sulfpryl chloride in 50 ml. of chloroform (purified by distillation from phosphorous pentoxide) are stirred with 3-4 mg. of a20- bis(isobutyronitrile) at room temperature under nitrogen. The crude product is obtained by evaporating by washing the chloroform solution and triturating the residue with hexane.

EXAMPLE I! EXAMPLE 19 Following the procedure of Example 6 bututilizing 7-phthalimido-3-methyl-A -cephem-4-carboxylic acid,

methyl ester in lieu of EA-(acetoxymethyD-l phthalimido-A -cephem-4-carboxylic acid, methyl ester, the product formed is 2-bromo-3-methyl-7- phthalimido-A -cephem-4-carboxylic acid, methyl es ter.

EXAMPLE 20 Following the procedure of Example? but utilizing Z-bromo-3-methyl-A -cephem-4-carboxylic acid, methyl ester in lieu of 3-(acetoxymethyl)-2-bromo-7- phthalimido-A -cephem-4-carboxylic acid, methyl ester, the product formed is 2-methoxy-3-methyl-7- phthalimido-A-cephem4-carboxylic acid, methyl ester.

EXAMPLE 21 2-Methoxy7-amino-cephalosporanic acid One millimole of 2-methoxy-3-(acetoxymethyl)-7- benzamido-A -cephem-4-carboxylic acid in 35 ml. absolute methylene chloride is treated with 79 mg. of pyridine and 150 mg. of trimethylchlorosilane added. After a short time (ca. 15 minutes), 1.2 g. of additional pyridine is added, followed by 832 mg. of phosphorous pentachloride at about 30 C. After one hour, the reaction vessel is chilled in an ice-salt bath, and 15 ml. of methanol added, the reaction mixture is stirred at 1() C. .for 30 minutes, then at 251- 5 C. for 30 minutes. Four ml. of 25 percent aqueous formic acid is added and the pH adjusted to 2.0 with triethylamineand the mixture filtered. After one-half hour, the pH is raised to about 3.5 until the amino acid precipitates. it is filtered off and washed with methanol to recover the desired product.

EXAMPLE 22 2-Methoxy-7amino-3-methyl-A -cephem-4-carboxylic acid Substitution of 2-methoxy-7-benzamido-3methyl- A -cephem-4-carboxylic acid in lieu of 2-methoxy-3- (acetoxymethyl)-7-benzamido-A -cephem-4- carboxylic acid in Example 2] gives the desired product.

EXAMPLES 23-36 7Acylamido-2-halo-cephalosporins (Table l) I General Procedure A mixture of l m mole of 7-acylamido substrate selected from group l and l m mole of the indicated halogenating agent from group II in 100 ml. of pure chloroform (freshly distilled from P 0 is treated with a few crystals of azo-bis-isobutyronitrile and placed under an inert (nitrogen or argon) atmosphere. The reaction mix is stirred for 6 to 8 hours at room temperature, then washed with cold 5 percent aqueous sodium bicarbonate solution, dried (Na SO filtered and evaporated to deposit the product indicated in compound Ill.

EXAMPLES 3753 7Acylamido-Z-substitutedcephaloporins (Table ll) General Procedure TABLE II ():-N -CH2A JOM N R M A R Solvent Substrate R O Br 43 d0. i --O- Br 44 CBILBCIIQCONII. C1130 Cl 45.. CHaCONH- C1130 CH'iC-O2 Cl -.A.-d O 46.. Thien2-y1CH2CONH- H0 CHaCOz Cl Dlmethoxythane. CH?=CI'ICH2SH CHzCH--CH2S 47 ..d0 H HO CHaCOa C1 r do Ally] alcohol CH=GHCH1O 48 "do H0 CII3CO2 Cl do CH3C:COI'I2OH... CIIilCEC-CHgO 4E)... Phthalinurlo. -O Br Acetonitnle OHaCOzH CHBCOQf 5O (1O. O-- Bl C5H5CO2 5 do O- Br CHaCOr- 5' (M1 0 CON]! CrJI CHz0 H 01 (11-13001- 53i (JulI5OCll C0NH 0511 011 0 ll Cl CH3CO2- What is claimed is: l. A compound of the formula:

phenyl fi thienyl phenylacetyl, thienylacetyl, phenoxyacetyl, or R and R taken together with the nitrogen atom to which they are attached form phthalimido; and R is selected from the group consisting of iodo, chloro, and bromo.

2. The compound in accordance with claim 1 wherein R and R taken together with the nitrogen atom to which they are attached form phthalimido.

3. The compound in accordance with claim 1 wherein R is hydrogen and R is selected from the group consisting of acetyl,

phenyl -43 thienyl fi phenylacetyl, thienylacetyl and phenoxyacetyl.

4. A compound in accordance with claim 2 having the name 7phthalimido-3hydroxymethyl-Z-bromo-A cephem-4-carboxylic acid y-lactone.

5. The compounds of claim 1 wherein R and R are hydrogen. 

1. A COMPOUND OF THE FORMULA:
 2. The compound in accordance with claim 1 wherein R1 and R2 taken together with the nitrogen atom to which they are attached form phthalimido.
 3. The compound in accordance with claim 1 wherein R2 is hydrogen and R1 is selected from the group consisting of acetyl,
 4. A compound in accordance with claim 2 having the name 7-phthalimido-3-hydroxymethyl-2-bromo- Delta 3-cephem-4-carboxylic acid gamma -lactone.
 5. The compounds of claim 1 wherein R1 and R2 are hydrogen. 